on the up side, while I was tearing out my hair and trawling the internet for knowledgez, I learned more about bundler and gemfile.lock and cap deploy:rollback and rails console (bundle exec rails console -e production
)

I had the same issue. I found that I needed to do the # ssh setup steps before I attempted cap deploy:setup. In the video, the ssh is done after and appears to be convenience only but in the show notes its before.